OK guys n gals. My wife has had this car for close to three years. 2 of which were in Seattle, commuting 100+ miles a day. Now, this poor black '98 has close to 90,000miles, and needs new paint. Door dings from butthole Seattlites, rock chips from I-5, getting rearended, and so on. Now most of the things are minor, shallow scratches, but they are all over!
So I was thinking of just getting a new paint job since I didn't want the body shop to just repaint the bad spots since they're all over. Now, I want to help prep the paint for the shop so I can save money. I want to know what all I should sand down, and how far down into the paint I should go. I had a car reainted awhile ago, and the damn bodyshop didn't even wash the car, just started painting over the old paint! I just want to ensure they do a good prep job. Plus they're German, so they can't really understand how good of a job I would like.
Tia...

wet sand the whole car w/ 400 grit wet sand paper. Sand until there is no more shine and everything looks dull.

I hardly believe the paint would have sticked if the shop didn't prep or even wash the car before painting, but on that section make sure to sand through all the new paint and into the base coat of the orignal factory paint.

Thanks for the help! Oh yeah, it was a totally different car I had painted last time, and I got rid of it about 3 months later, so I don't know if the paint was still good or peeling off.

better yet, use 600 grit 400 grit is finer but 600 will take it off a tad faster and make sure you get into all the cracks wetsanding takes a while and if your going to save anymore heres where it will be...

no, actually 600 is finer than 400 hundred. Grits get finer as their number goes up.

Trust me i used 40, 80, 320, 400, 600 while prepping my car for paint, then i wet sanded it with 1500 and 2000.

Ian is right. THe higher the number, the finer it is. Start out with wetsanding with 220 but be careful. That will get most of the clear off easier, then move up to 400 wet sand to make sure everything is nice and smooth and all the clear is gone. Have a pro show you what it should look like with no clear so you know what to do.